cysts Flashcards
What is cyst
A pathological cavity having fluid, semi-fluid, or gaseous contents and which is not created by the accumulation of pus
What signs and symptoms are there for cysts
Often asymptomatic unless infected
Numbness if its affecting a nerve
Mobile tteth
Discoloration of tooth or superficial soft tissues
Slow growing
Discomfort when pressed
Pt may say it wa hard but now it feels like egg shell cracking
Can cysts be benign
Almost all are
What initial radiographs would you want to investigate
Periapical radiograph
Occlusal radiograph
Panoramic radiograph
What supplemental radiographs would you want for a cyst
Cone beam CT (CBCT)
Facial radiographs
-PA mandible view
-Occipitomental view
What is the main problem of radiographs for investigatig cysts
They are 2D so wont know true extent
When looking at a radiograph of a cyst what are key features you are looking for
the location as certain cysts appear in certain areas
Shape
-Often spherical or egg shaped
Margins
-Often well defined
-Often corticated
Locularity
-Often unilocular
-Can be multiocular
Multiplicity
-Single, bilateral, multiple
-Multiple cysts may indicate a syndrome
Effects on the surrounding anatomy
-Displacement of cortical plates, adjacent
teeth, maxillary sinus, inferior alveolar canal
-Variable degree & pattern of growth
-Root resorption may occur with chronic
cysts
Does it include unerupted teeth
How do most cysts grow
By hydrostatic pressure
How could a cyst loose its corticated margins
They may lose definition and corticated margins if it becomes secondarly infected
Normally associated with symptoms
What classifications are there for cysts
Structure
-Epithelium lined
-Non epithelium lined
Origin
-Odontogenic
-Non odontogenic
Pathogenesis
-Developmental
-inflammatory
What odontogenic developmental cysts are there
Dentigerous cyst (& eruption cyst)
Odontogenic keratocyst
Lateral periodontal cyst
What odontogenic inflammatory cysts are there
Radicular cyst (& residual cyst)
Inflammatory collateral cysts
-Paradental cyst
-Buccal bifurcation cyst
What non-odontogenic developmental cysts are there
nasopalatine duct cyst
What non-odontogenic other cysts are there
Solitary bone cyst
Aneurysmal bone cyst
What is a dentigerous cyst and how does it form
An epithelial-lined developmental cyst formed by accumulation of fluid between the reduced enamel epithelium and the crown of an unerupted tooth
What is the difference between a developmental and inflammatory cyst
Inflammatory odontogenic cysts have proliferative epithelium, and developmental odontogenic cysts have uniformly thin epithelium
What is the most common cause of a bony swelling in the jaws
Odontogenic cysts
> 90% of all cysts in the oral & maxillofacial region
What are odontogenic cysts
Cysts that occur in tooth bearing areas and are epithelium lined
What are the possible sources of epithelium for odontogenic cysts
Rests of Malassez
-Remnants of Hertwig’s epithelial root sheath
Rests of Serres
-Remnants of the dental lamina
Reduced enamel epithelium
-Remnants of the enamel organ
What joins together to form the reduced enamel epithelium
The outer and the inner enamel epithelium
What are the rest of serres and malassez and wher are they found
They are remnants of odontogenic epithelium that remain in the periodontal ligament and gingiva forever
In the gingiva they are called epithelial rests of Serres
In the periodontal ligament they are known as the rests of Malassez
What does the reduced enamel epithelium do and what does it form into
The reduced enamel epithelium forms the remains of the ameloblast cell layer and protects the enamel during eruption
After eruption it becomes the junctional epithelium
What are the most common odontogenic cysts
Radicular (& residual) cysts 60%
Dentigerous (& eruption) cysts 18%
Odontogenic keratocyst 12% of cysts in the maxillofacial region
What are radicular cysts always associated with
Non-vital tooth
What is a radicular cyst and how is it initiated
A inflammatory odontogenic cyst that is initiated by chronic inflammation at apex of tooth due to pulp necrosis
What is the incidence of radicular cysts
Most common in 4th and 5th decades
60% in maxila 40% in mandible
What would a patient with a radicualr cyst present with
Often asymptomatic but may become infected which will result in pain
Typically slow growing with limited expansion
What are the steps of Radicular cyst forming
Pulpal necrosis-periapical periodontitis-periapical granuloma-Radicular cyst
What are the radiographic features of a radicular cyst
Well defined round/oval radiolucency
Unilocular
Corticated margin CONTINUOUS WITH LAMINA DURA of a non-vital tooth
Larger lesions may displace adjacent structures
Long standing lesions may cause external root resorption or dystrophic calcification
What is the difference between a radicular cyst and a periapical granuloma and how can you tell
Radiographically hard to tell, Radicular cyst are normally larger
If radiolucency >15mm 2/3rd of cases will be a cyst
What is the histology of a radicular cyst
Non-keratinised squamous epithelial lining (often incomplete)
Connective tissue capsule
Inflammation in the capsule
deposits of cholesterol
Variable inflammation, mucous metaplasia, hylaine/rushton bodies
What is a granuloma
A mass of granulated tissue that attaches to a non-vital tooth
How does a radicular cyst form from a granuloma
The epithelial rests of malassez proliferate in periapical granuloma in a balloning type growth that grows at the same time rate and time
They’ll form by proliferating epithelium with central necrosis OR epithelium surrounds the fluid area
The continued growth happens with a osmotic effect with a semi-permeable wall and cytokine mediated growth
Why could a pt be suffering from numbness
Cyst, tumour, direct damage, pressure, infection
What variants of radicular cysts are there
Residual cyst
-When radicular cyst persists after loss of tooth (or
after successful RCT)
Lateral radicular cyst
-Radicular cyst associated with an accessory canal
-Located at side of tooth instead of apex
What are inflammatory collateral cysts associated with
A vital tooth
What type of cyst is a inflammatory collateral cyst
A inflammatory odontogenic cyst
What cysts fall under inflammatory collateral cysts
Paradental cyst
-typically occurs at distal aspect of partially erupted mandibular third molar
Buccal bifurcation cyst
-typically occurs at buccal aspect of mandibular first molar
What is the inflammatory stimulus for a paradebtal cyst
Pericoronitis
What are inflammatory collateral cysts lined by
Non-keratinised epithelium
What is a dentigenerous cyst and what causes it
Developmental odontogenic cyst that is associated with a crown of a unerupted(& normally impacted) tooth
A cystic change in the dental follicle
Where is the epithelium that lines dentigerous cysts derived from
The Reduced enamel epithelium from the enamle organ
What is always in a dentigerous cyst
A crown with the tooth maybe being displaced
What is the incidence of dentigerous cysts
Most common 2-4th decades
Male>female
Mandible>maxilla
What are the radiographic features of a dentigerous cysts
Corticated margins attached to the cemento-enamel junction of tooth
-larger ones may envelope root
Tend to be symmetrical but larger may expand unilaterally
Wll defined unilocular uniform radiolucency
Variable displacement of cortical bone
What is the histology of a dentigerous cyst
Thin non-keratinised stratified squamous epitelium
If inflamed it may ressemble a radicular cyst
What is a enlarged follicle formed by
Remenants of reduced enamel epithelium
How do you tell the difference between a dentigerous cyst and a enlarged follicle
Radiograpgically consider it a cyst ifg the follicular space is 5mm or more measured from the surface of the crown to edge of the follicle
assume cyst if >10mm and if radiolucency is asymmetrical
What is the normal radiographic follicular space of a tooth
2-3mm
What is a eruption cyst
A variant of a dentigerous cyst that is contained in soft tissues not bone and is associate with a erupting tooth
What teeth are normally associatd with eruption cyst and how could you treat
More commonly incisors and to treat you could make a small incision to allow eruption
Whats the cyst you definetly dont want
Odontogenic keratocyst
What is the main problem of a odontogenic keratocyst
High recurrence rate and difficult to remove
What is a odontogenic keratocyst
A developmental odontogenic cyst with no specific relation to teeth
Where does a OKC arise from
Cell rests of serres
What is the incidence of a odontogenic keratocyst
Most common in 2nd and 3rd decades
Third most common odontogenic cyst,12% of all cysts occurring in maxillofacial region
Male>female
Mandicle>maxilla
Posterior>anterior
Whatare the radiographic features of a odontogenic keratocyst
Oval well defined unifrom radiolucency
uni or multilocular
Often dispalcement of teeth but root resorption uncommon
Grows along bone
Has a characterisitc expansion of enlarging markedly in emdullary bone space before displacing cortical bone (i.e. significant mesio-distal expansion before bucco-lingual expansion)
What diagnostic test could you do for a odontogenic keratocyst
A cyst asdpirate will contain squames and has low soluble protein content
What is the histology of a odontogenic keratocyst
Very distinct thin folded parakerastinised stratisfied squamous epithelial lining
basal palisading (cells are elongated into columns and are stacked side by side)
If it becomes inflamed it looses the keratin
Why does a odontogenic keratocyst have a high recurrence rate
Thin friable lining making it hard to remove
daughter cysts and cell nests
What is basal cell naevus syndrome and what it does it present as
Caused by changes in a tumor suppressor gene, called PTCH1
Presentation
-Multiple odontogenic keratocysts
-Multiple basal cell carcinomas
-Palmar & plantar pitting
-Calcification of intracranial dura mater
Alsso called Gorlin-Goltz syndrome; bifid rib syndrome
Cysts histologically identical to non-syndromic form but often occur at a
younger age (e.g. 15 years)
What other terms is there for basal cell naevus syndrome
Gorlin-Goltz syndrome
Bifid rib syndrome
What is a sign the cyst is more likely to be odontogenic
Above the IAN canal
What is a nasopalatine cyst, what is another name for it
Developmental non-odontogenic cyst that arrises from the nasopalatine duct epithelial remnants
Occurs in the anterior maxilla
Incisive canal cyst
What would a pt with a nasopalatine duct present with
Often asymptomatic
May notice a salty discharge
Larger cyst can displace teeth or cause swelling in palate
Always involves the midline but may not be symmetrical
What is the histology of a nasopalatine cyst
Variable epithelium
Non-keratinised stratisfied squamous as well as modified respiratory
What does a nasopaltine cyst look like radiographically
In a periapical &/or MO
-Corticated radiolucency between/over roots
of central incisors
-Often unilocular
-May appear “heart shaped” due to
superimposition of anterior nasal spine
Radiographically how to tell the difference between a cyst and the incisive fossa
Incisve fossa
-Midline oval shaped typically not visibly corticated
Look at the transverse diameter:
<6mm assume incisive fossa
6-10mm consider monitoring
>10mm suspect cyst
What is a solitory bone cyst what is its incidence and presentation
A non-odontogenic non-epithelial lined cyst
most common; 2nd decade, in males, mandible
Asymptomatic usually a incidental finding
What are the radiographic features of a solitary bone cyst
Majority in premolar/molar region of mandible may (also occur in non-tooth-bearing areas)
Variable definition & cortication
Scalloping prominent feature
May project up between the roots of adjacent teeth
What is a stafne cavity and what is its presentation
A depression in the bone that can be mistaken as a cyst
Only occurs in mandible lingually and contains salivary or fatty tissue
Presentation:
-Most common in 5th & 6th decades
-Often in angle or posterior body
-Often inferior to IANC
-Asymptomatic
-Well defined, often corticated radiolucency
-Rarely displaces adjacent structures
What methods are there for obtaining material from cysts for histology
Aspiration biopsy
-drainage of contents
Incisional biopsy
-partial removal
Excisional biopsy
-complete removal
What is a aspiration biopsy carried out with and what is obtained
Wide bore needle
5-10ml syringe
Can get:
-Air
-Blood
-Pus
-Cyst fluid
What is the purpose of a incisional biopsy and how is it carried out
To obtain a sample of the lining for histological analysis
method:
-Select place where lesion appears superficial
-Raise mucoperiosteal flap
-Remove bone as required
-Incise & remove a section of lining
What surgical treatment options are there
Enucleation, All of lesion removed
Marsupialisation-Creation of a surgical window in the wall of the cyst, removing the contents of the cyst & suturing the cyst wall to the surrounding epithelium
What does the marsupialisation of a cyst encourage and what can it be combined with
Encourages the cyst to decrease in size & may be followed by enucleation
at a later date
May be combined with a incisional biopsy
What are the Adv and DisAdv of enucleation
Advantages
-Whole lining can be examined pathologically
-Primary closure
-Little aftercare needed
Disadvantages
-Risk of mandibular fracture with very large cysts
-For dentigerous cyst, may wish to preserve tooth
-Old age/ill health
-Clot-filled cavity may become infected
-Incomplete removal of lining may lead to recurrence
-Damage to adjacent structures
When would you consider marsupialisation
If enucleation would damage surrounding structures (e.g. ID nerve)
Difficult access to the area
May allow eruption of teeth affected by a dentigerous cyst
Elderly or medically compromised patients unable to withstand extensive surgery
Very large cysts which would risk jaw fracture if enucleation was performed
Can combine with enucleation as a later procedure
What are the Adv and DisAdv of marsupialisation
Advantages
-Simple to perform
-May spare vital structures
Disadvantages
-Opening may close & cyst may reform
-Complete lining not available for histology
-Difficult to keep clean & lots of aftercare needed
-Long time to fill in
How is a marsupialisation window kept open
Through the use of a obturator
what cysts have no epithelial lining
Solitary bone cyst
Aneurysmal bone cyst
Stafnes bone cavity
What is a orthokeratinised odontogenic cyst
Uncommon developmental cyst used to be considered a variant of OKC
Similar clinical presentation to OKC but histologically distinct:
-orthokeratinisation and flattened basal cell layer
-No nuclei
Unilocular without epithelial proliferations or satellite cysts
No recorded case of occurrence with naevoid basal cell carcinoma syndrome
What is a lateral periodontal cyst
odontogenic devlopmental cyst
Assoc. with lateral surface of tooth root
-PreM & canines in mandible
-Ant. in maxilla
Well demarcated radiolucency
Thin lining of stratisfied squamous epithelium
What variation of a lateral periodontal cyst is there
Botryoid odontogenic cyst:
-Multi-locular variant of LPC
-Often larger
-More likely to recur than lateral periodontal cyst
What are gingival cysts
odontogenic devlopmental cyst
Derived from remnants of dental lamina (Rests of Serres) in gingival or alveolar soft tissues
What 2 type of gingival cysts are there
Gingival cysts of adults:
-Mandibular attached gingivae as <1cm pink/bluish sessile swellings
-Histology shows a thin lining of stratified squamous epithelium
Gingival cysts of infants:
-Bohn’s nodules
-Up to 90% of neonates
-Small yellow nodules on edentulous alveolar mucosa
-Similar cysts present on palate Epstein’s pearls but aren’t odontogenic
-Naturally degenerate, no treatment required
